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8efc0c15 | 1 | /* |
5260325f | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
bcbf86ec | 5 | * This program is the ssh daemon. It listens for connections from clients, |
6 | * and performs authentication, executes use commands or shell, and forwards | |
5260325f | 7 | * information to/from the application to the user client over an encrypted |
bcbf86ec | 8 | * connection. This can also handle forwarding of X11, TCP/IP, and |
9 | * authentication agent connections. | |
e78a59f5 | 10 | * |
bcbf86ec | 11 | * As far as I am concerned, the code I have written for this software |
12 | * can be used freely for any purpose. Any derived versions of this | |
13 | * software must be clearly marked as such, and if the derived work is | |
14 | * incompatible with the protocol description in the RFC file, it must be | |
15 | * called by a name other than "ssh" or "Secure Shell". | |
16 | * | |
17 | * SSH2 implementation: | |
1853d1ef | 18 | * Privilege Separation: |
bcbf86ec | 19 | * |
1853d1ef | 20 | * Copyright (c) 2000, 2001, 2002 Markus Friedl. All rights reserved. |
21 | * Copyright (c) 2002 Niels Provos. All rights reserved. | |
bcbf86ec | 22 | * |
23 | * Redistribution and use in source and binary forms, with or without | |
24 | * modification, are permitted provided that the following conditions | |
25 | * are met: | |
26 | * 1. Redistributions of source code must retain the above copyright | |
27 | * notice, this list of conditions and the following disclaimer. | |
28 | * 2. Redistributions in binary form must reproduce the above copyright | |
29 | * notice, this list of conditions and the following disclaimer in the | |
30 | * documentation and/or other materials provided with the distribution. | |
31 | * | |
32 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
33 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
34 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
35 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
36 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
37 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
38 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
39 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
40 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
41 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
5260325f | 42 | */ |
8efc0c15 | 43 | |
44 | #include "includes.h" | |
bd7c69ea | 45 | |
aa2eae64 | 46 | #include <sys/types.h> |
4095f623 | 47 | #ifdef HAVE_SYS_STAT_H |
48 | # include <sys/stat.h> | |
49 | #endif | |
50 | #include <sys/ioctl.h> | |
aa2eae64 | 51 | #include <sys/wait.h> |
a75f5360 | 52 | |
b5b88c19 | 53 | #ifdef HAVE_PATHS_H |
a75f5360 | 54 | #include <paths.h> |
b5b88c19 | 55 | #endif |
ada68823 | 56 | #include <signal.h> |
8efc0c15 | 57 | |
42f11eb2 | 58 | #include <openssl/dh.h> |
59 | #include <openssl/bn.h> | |
436c347c | 60 | #include <openssl/md5.h> |
1853d1ef | 61 | #include <openssl/rand.h> |
6e879cb4 | 62 | #ifdef HAVE_SECUREWARE |
63 | #include <sys/security.h> | |
64 | #include <prot.h> | |
65 | #endif | |
42f11eb2 | 66 | |
67 | #include "ssh.h" | |
68 | #include "ssh1.h" | |
69 | #include "ssh2.h" | |
8efc0c15 | 70 | #include "xmalloc.h" |
71 | #include "rsa.h" | |
1729c161 | 72 | #include "sshpty.h" |
8efc0c15 | 73 | #include "packet.h" |
42f11eb2 | 74 | #include "log.h" |
8efc0c15 | 75 | #include "servconf.h" |
76 | #include "uidswap.h" | |
77 | #include "compat.h" | |
7368a6c8 | 78 | #include "buffer.h" |
b9a549d7 | 79 | #include "bufaux.h" |
42f11eb2 | 80 | #include "cipher.h" |
e78a59f5 | 81 | #include "kex.h" |
7368a6c8 | 82 | #include "key.h" |
94ec8c6b | 83 | #include "dh.h" |
e78a59f5 | 84 | #include "myproposal.h" |
a306f2dd | 85 | #include "authfile.h" |
42f11eb2 | 86 | #include "pathnames.h" |
87 | #include "atomicio.h" | |
88 | #include "canohost.h" | |
89 | #include "auth.h" | |
90 | #include "misc.h" | |
b9a549d7 | 91 | #include "msg.h" |
a5c9ffdb | 92 | #include "dispatch.h" |
e4d7f734 | 93 | #include "channels.h" |
1b34c1b3 | 94 | #include "session.h" |
1853d1ef | 95 | #include "monitor_mm.h" |
96 | #include "monitor.h" | |
97 | #include "monitor_wrap.h" | |
98 | #include "monitor_fdpass.h" | |
8efc0c15 | 99 | |
100 | #ifdef LIBWRAP | |
101 | #include <tcpd.h> | |
102 | #include <syslog.h> | |
103 | int allow_severity = LOG_INFO; | |
104 | int deny_severity = LOG_WARNING; | |
105 | #endif /* LIBWRAP */ | |
106 | ||
107 | #ifndef O_NOCTTY | |
108 | #define O_NOCTTY 0 | |
109 | #endif | |
110 | ||
b250e837 | 111 | /* Re-exec fds */ |
112 | #define REEXEC_DEVCRYPTO_RESERVED_FD (STDERR_FILENO + 1) | |
113 | #define REEXEC_STARTUP_PIPE_FD (STDERR_FILENO + 2) | |
114 | #define REEXEC_CONFIG_PASS_FD (STDERR_FILENO + 3) | |
115 | #define REEXEC_MIN_FREE_FD (STDERR_FILENO + 4) | |
116 | ||
260d427b | 117 | extern char *__progname; |
260d427b | 118 | |
8efc0c15 | 119 | /* Server configuration options. */ |
120 | ServerOptions options; | |
121 | ||
122 | /* Name of the server configuration file. */ | |
42f11eb2 | 123 | char *config_file_name = _PATH_SERVER_CONFIG_FILE; |
8efc0c15 | 124 | |
5260325f | 125 | /* |
126 | * Debug mode flag. This can be set on the command line. If debug | |
127 | * mode is enabled, extra debugging output will be sent to the system | |
128 | * log, the daemon will not go to background, and will exit after processing | |
129 | * the first connection. | |
130 | */ | |
8efc0c15 | 131 | int debug_flag = 0; |
132 | ||
f87f09aa | 133 | /* Flag indicating that the daemon should only test the configuration and keys. */ |
134 | int test_flag = 0; | |
135 | ||
8efc0c15 | 136 | /* Flag indicating that the daemon is being started from inetd. */ |
137 | int inetd_flag = 0; | |
138 | ||
0b6fbf03 | 139 | /* Flag indicating that sshd should not detach and become a daemon. */ |
140 | int no_daemon_flag = 0; | |
141 | ||
6a17f9c2 | 142 | /* debug goes to stderr unless inetd_flag is set */ |
143 | int log_stderr = 0; | |
144 | ||
8efc0c15 | 145 | /* Saved arguments to main(). */ |
146 | char **saved_argv; | |
4d33e531 | 147 | int saved_argc; |
8efc0c15 | 148 | |
b9a549d7 | 149 | /* re-exec */ |
150 | int rexeced_flag = 0; | |
151 | int rexec_flag = 1; | |
152 | int rexec_argc = 0; | |
153 | char **rexec_argv; | |
154 | ||
aa3378df | 155 | /* |
48e671d5 | 156 | * The sockets that the server is listening; this is used in the SIGHUP |
157 | * signal handler. | |
aa3378df | 158 | */ |
48e671d5 | 159 | #define MAX_LISTEN_SOCKS 16 |
160 | int listen_socks[MAX_LISTEN_SOCKS]; | |
161 | int num_listen_socks = 0; | |
8efc0c15 | 162 | |
aa3378df | 163 | /* |
164 | * the client's version string, passed by sshd2 in compat mode. if != NULL, | |
165 | * sshd will skip the version-number exchange | |
166 | */ | |
5260325f | 167 | char *client_version_string = NULL; |
7368a6c8 | 168 | char *server_version_string = NULL; |
8efc0c15 | 169 | |
7a37c112 | 170 | /* for rekeying XXX fixme */ |
171 | Kex *xxx_kex; | |
172 | ||
aa3378df | 173 | /* |
174 | * Any really sensitive data in the application is contained in this | |
175 | * structure. The idea is that this structure could be locked into memory so | |
176 | * that the pages do not get written into swap. However, there are some | |
177 | * problems. The private key contains BIGNUMs, and we do not (in principle) | |
178 | * have access to the internals of them, and locking just the structure is | |
179 | * not very useful. Currently, memory locking is not implemented. | |
180 | */ | |
5260325f | 181 | struct { |
cb7bd922 | 182 | Key *server_key; /* ephemeral server key */ |
fa08c86b | 183 | Key *ssh1_host_key; /* ssh1 host key */ |
184 | Key **host_keys; /* all private host keys */ | |
185 | int have_ssh1_key; | |
186 | int have_ssh2_key; | |
00be5382 | 187 | u_char ssh1_cookie[SSH_SESSION_KEY_LENGTH]; |
8efc0c15 | 188 | } sensitive_data; |
189 | ||
aa3378df | 190 | /* |
59c97189 | 191 | * Flag indicating whether the RSA server key needs to be regenerated. |
192 | * Is set in the SIGALRM handler and cleared when the key is regenerated. | |
aa3378df | 193 | */ |
7a934d1b | 194 | static volatile sig_atomic_t key_do_regen = 0; |
8efc0c15 | 195 | |
c9130033 | 196 | /* This is set to true when a signal is received. */ |
7a934d1b | 197 | static volatile sig_atomic_t received_sighup = 0; |
198 | static volatile sig_atomic_t received_sigterm = 0; | |
8efc0c15 | 199 | |
7368a6c8 | 200 | /* session identifier, used by RSA-auth */ |
1e3b8b07 | 201 | u_char session_id[16]; |
e7c0f9d5 | 202 | |
a306f2dd | 203 | /* same for ssh2 */ |
1e3b8b07 | 204 | u_char *session_id2 = NULL; |
a27002e5 | 205 | u_int session_id2_len = 0; |
a306f2dd | 206 | |
c345cf9d | 207 | /* record remote hostname or ip */ |
1e3b8b07 | 208 | u_int utmp_len = MAXHOSTNAMELEN; |
c345cf9d | 209 | |
7ace8c3b | 210 | /* options.max_startup sized array of fd ints */ |
211 | int *startup_pipes = NULL; | |
212 | int startup_pipe; /* in child */ | |
213 | ||
1853d1ef | 214 | /* variables used for privilege separation */ |
98a58eda | 215 | int use_privsep; |
a9b33b95 | 216 | struct monitor *pmonitor = NULL; |
1853d1ef | 217 | |
2362db19 | 218 | /* global authentication context */ |
219 | Authctxt *the_authctxt = NULL; | |
220 | ||
be2ca0c9 | 221 | /* message to be displayed after login */ |
222 | Buffer loginmsg; | |
223 | ||
7368a6c8 | 224 | /* Prototypes for various functions defined later in this file. */ |
396c147e | 225 | void destroy_sensitive_data(void); |
1853d1ef | 226 | void demote_sensitive_data(void); |
c8d54615 | 227 | |
396c147e | 228 | static void do_ssh1_kex(void); |
229 | static void do_ssh2_kex(void); | |
94ec8c6b | 230 | |
48e671d5 | 231 | /* |
232 | * Close all listening sockets | |
233 | */ | |
396c147e | 234 | static void |
48e671d5 | 235 | close_listen_socks(void) |
236 | { | |
237 | int i; | |
e424e241 | 238 | |
48e671d5 | 239 | for (i = 0; i < num_listen_socks; i++) |
240 | close(listen_socks[i]); | |
241 | num_listen_socks = -1; | |
242 | } | |
243 | ||
7ace8c3b | 244 | static void |
245 | close_startup_pipes(void) | |
246 | { | |
247 | int i; | |
e424e241 | 248 | |
7ace8c3b | 249 | if (startup_pipes) |
250 | for (i = 0; i < options.max_startups; i++) | |
251 | if (startup_pipes[i] != -1) | |
252 | close(startup_pipes[i]); | |
253 | } | |
254 | ||
5260325f | 255 | /* |
256 | * Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP; | |
257 | * the effect is to reread the configuration file (and to regenerate | |
258 | * the server key). | |
259 | */ | |
3efa8ea9 | 260 | |
261 | /*ARGSUSED*/ | |
396c147e | 262 | static void |
5260325f | 263 | sighup_handler(int sig) |
8efc0c15 | 264 | { |
6056eb35 | 265 | int save_errno = errno; |
266 | ||
5260325f | 267 | received_sighup = 1; |
268 | signal(SIGHUP, sighup_handler); | |
6056eb35 | 269 | errno = save_errno; |
8efc0c15 | 270 | } |
271 | ||
5260325f | 272 | /* |
273 | * Called from the main program after receiving SIGHUP. | |
274 | * Restarts the server. | |
275 | */ | |
396c147e | 276 | static void |
5ca51e19 | 277 | sighup_restart(void) |
8efc0c15 | 278 | { |
bbe88b6d | 279 | logit("Received SIGHUP; restarting."); |
48e671d5 | 280 | close_listen_socks(); |
7ace8c3b | 281 | close_startup_pipes(); |
5260325f | 282 | execv(saved_argv[0], saved_argv); |
bbe88b6d | 283 | logit("RESTART FAILED: av[0]='%.100s', error: %.100s.", saved_argv[0], |
e424e241 | 284 | strerror(errno)); |
5260325f | 285 | exit(1); |
8efc0c15 | 286 | } |
287 | ||
5260325f | 288 | /* |
289 | * Generic signal handler for terminating signals in the master daemon. | |
5260325f | 290 | */ |
3efa8ea9 | 291 | /*ARGSUSED*/ |
396c147e | 292 | static void |
5260325f | 293 | sigterm_handler(int sig) |
8efc0c15 | 294 | { |
c9130033 | 295 | received_sigterm = sig; |
8efc0c15 | 296 | } |
297 | ||
5260325f | 298 | /* |
299 | * SIGCHLD handler. This is called whenever a child dies. This will then | |
c9130033 | 300 | * reap any zombies left by exited children. |
5260325f | 301 | */ |
3efa8ea9 | 302 | /*ARGSUSED*/ |
396c147e | 303 | static void |
5260325f | 304 | main_sigchld_handler(int sig) |
8efc0c15 | 305 | { |
5260325f | 306 | int save_errno = errno; |
e424e241 | 307 | pid_t pid; |
5260325f | 308 | int status; |
5ad13cd7 | 309 | |
8c38e88b | 310 | while ((pid = waitpid(-1, &status, WNOHANG)) > 0 || |
311 | (pid < 0 && errno == EINTR)) | |
5260325f | 312 | ; |
5ad13cd7 | 313 | |
5260325f | 314 | signal(SIGCHLD, main_sigchld_handler); |
315 | errno = save_errno; | |
8efc0c15 | 316 | } |
317 | ||
5260325f | 318 | /* |
319 | * Signal handler for the alarm after the login grace period has expired. | |
320 | */ | |
3efa8ea9 | 321 | /*ARGSUSED*/ |
396c147e | 322 | static void |
5260325f | 323 | grace_alarm_handler(int sig) |
8efc0c15 | 324 | { |
c9130033 | 325 | /* XXX no idea how fix this signal handler */ |
326 | ||
a9b33b95 | 327 | if (use_privsep && pmonitor != NULL && pmonitor->m_pid > 0) |
328 | kill(pmonitor->m_pid, SIGALRM); | |
329 | ||
5260325f | 330 | /* Log error and exit. */ |
26b9a3d2 | 331 | fatal("Timeout before authentication for %s", get_remote_ipaddr()); |
5260325f | 332 | } |
8efc0c15 | 333 | |
5260325f | 334 | /* |
335 | * Signal handler for the key regeneration alarm. Note that this | |
336 | * alarm only occurs in the daemon waiting for connections, and it does not | |
337 | * do anything with the private key or random state before forking. | |
338 | * Thus there should be no concurrency control/asynchronous execution | |
339 | * problems. | |
340 | */ | |
396c147e | 341 | static void |
cb7bd922 | 342 | generate_ephemeral_server_key(void) |
fa08c86b | 343 | { |
7fdc56c5 | 344 | u_int32_t rnd = 0; |
00be5382 | 345 | int i; |
346 | ||
cd332296 | 347 | verbose("Generating %s%d bit RSA key.", |
76ca7b01 | 348 | sensitive_data.server_key ? "new " : "", options.server_key_bits); |
fa08c86b | 349 | if (sensitive_data.server_key != NULL) |
350 | key_free(sensitive_data.server_key); | |
cd332296 | 351 | sensitive_data.server_key = key_generate(KEY_RSA1, |
76ca7b01 | 352 | options.server_key_bits); |
353 | verbose("RSA key generation complete."); | |
00be5382 | 354 | |
355 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
356 | if (i % 4 == 0) | |
7fdc56c5 | 357 | rnd = arc4random(); |
358 | sensitive_data.ssh1_cookie[i] = rnd & 0xff; | |
359 | rnd >>= 8; | |
00be5382 | 360 | } |
361 | arc4random_stir(); | |
fa08c86b | 362 | } |
f546c780 | 363 | |
3efa8ea9 | 364 | /*ARGSUSED*/ |
396c147e | 365 | static void |
5260325f | 366 | key_regeneration_alarm(int sig) |
367 | { | |
368 | int save_errno = errno; | |
e424e241 | 369 | |
59c97189 | 370 | signal(SIGALRM, SIG_DFL); |
5260325f | 371 | errno = save_errno; |
59c97189 | 372 | key_do_regen = 1; |
5260325f | 373 | } |
8efc0c15 | 374 | |
396c147e | 375 | static void |
7368a6c8 | 376 | sshd_exchange_identification(int sock_in, int sock_out) |
377 | { | |
2ceb8101 | 378 | u_int i; |
379 | int mismatch; | |
7368a6c8 | 380 | int remote_major, remote_minor; |
a8be9f80 | 381 | int major, minor; |
7368a6c8 | 382 | char *s; |
383 | char buf[256]; /* Must not be larger than remote_version. */ | |
384 | char remote_version[256]; /* Must be at least as big as buf. */ | |
385 | ||
a8be9f80 | 386 | if ((options.protocol & SSH_PROTO_1) && |
387 | (options.protocol & SSH_PROTO_2)) { | |
388 | major = PROTOCOL_MAJOR_1; | |
389 | minor = 99; | |
390 | } else if (options.protocol & SSH_PROTO_2) { | |
391 | major = PROTOCOL_MAJOR_2; | |
392 | minor = PROTOCOL_MINOR_2; | |
393 | } else { | |
394 | major = PROTOCOL_MAJOR_1; | |
395 | minor = PROTOCOL_MINOR_1; | |
396 | } | |
397 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", major, minor, SSH_VERSION); | |
7368a6c8 | 398 | server_version_string = xstrdup(buf); |
399 | ||
7b390973 | 400 | /* Send our protocol version identification. */ |
401 | if (atomicio(vwrite, sock_out, server_version_string, | |
402 | strlen(server_version_string)) | |
403 | != strlen(server_version_string)) { | |
404 | logit("Could not write ident string to %s", get_remote_ipaddr()); | |
2362db19 | 405 | cleanup_exit(255); |
7b390973 | 406 | } |
407 | ||
408 | /* Read other sides version identification. */ | |
409 | memset(buf, 0, sizeof(buf)); | |
410 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
411 | if (atomicio(read, sock_in, &buf[i], 1) != 1) { | |
412 | logit("Did not receive identification string from %s", | |
413 | get_remote_ipaddr()); | |
2362db19 | 414 | cleanup_exit(255); |
7368a6c8 | 415 | } |
7b390973 | 416 | if (buf[i] == '\r') { |
417 | buf[i] = 0; | |
418 | /* Kludge for F-Secure Macintosh < 1.0.2 */ | |
419 | if (i == 12 && | |
420 | strncmp(buf, "SSH-1.5-W1.0", 12) == 0) | |
7368a6c8 | 421 | break; |
7b390973 | 422 | continue; |
423 | } | |
424 | if (buf[i] == '\n') { | |
425 | buf[i] = 0; | |
426 | break; | |
7368a6c8 | 427 | } |
7368a6c8 | 428 | } |
7b390973 | 429 | buf[sizeof(buf) - 1] = 0; |
430 | client_version_string = xstrdup(buf); | |
7368a6c8 | 431 | |
432 | /* | |
433 | * Check that the versions match. In future this might accept | |
434 | * several versions and set appropriate flags to handle them. | |
435 | */ | |
436 | if (sscanf(client_version_string, "SSH-%d.%d-%[^\n]\n", | |
437 | &remote_major, &remote_minor, remote_version) != 3) { | |
6ae2364d | 438 | s = "Protocol mismatch.\n"; |
dc54438a | 439 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 440 | close(sock_in); |
441 | close(sock_out); | |
bbe88b6d | 442 | logit("Bad protocol version identification '%.100s' from %s", |
7368a6c8 | 443 | client_version_string, get_remote_ipaddr()); |
2362db19 | 444 | cleanup_exit(255); |
7368a6c8 | 445 | } |
446 | debug("Client protocol version %d.%d; client software version %.100s", | |
184eed6a | 447 | remote_major, remote_minor, remote_version); |
7368a6c8 | 448 | |
e78a59f5 | 449 | compat_datafellows(remote_version); |
450 | ||
9a87e2ac | 451 | if (datafellows & SSH_BUG_PROBE) { |
bbe88b6d | 452 | logit("probed from %s with %s. Don't panic.", |
9a87e2ac | 453 | get_remote_ipaddr(), client_version_string); |
2362db19 | 454 | cleanup_exit(255); |
9a87e2ac | 455 | } |
456 | ||
3a1c54d4 | 457 | if (datafellows & SSH_BUG_SCANNER) { |
bbe88b6d | 458 | logit("scanned from %s with %s. Don't panic.", |
3a1c54d4 | 459 | get_remote_ipaddr(), client_version_string); |
2362db19 | 460 | cleanup_exit(255); |
3a1c54d4 | 461 | } |
462 | ||
a8be9f80 | 463 | mismatch = 0; |
6aacefa7 | 464 | switch (remote_major) { |
7368a6c8 | 465 | case 1: |
a306f2dd | 466 | if (remote_minor == 99) { |
467 | if (options.protocol & SSH_PROTO_2) | |
468 | enable_compat20(); | |
469 | else | |
470 | mismatch = 1; | |
471 | break; | |
472 | } | |
a8be9f80 | 473 | if (!(options.protocol & SSH_PROTO_1)) { |
474 | mismatch = 1; | |
475 | break; | |
476 | } | |
7368a6c8 | 477 | if (remote_minor < 3) { |
089fbbd2 | 478 | packet_disconnect("Your ssh version is too old and " |
7368a6c8 | 479 | "is no longer supported. Please install a newer version."); |
480 | } else if (remote_minor == 3) { | |
481 | /* note that this disables agent-forwarding */ | |
482 | enable_compat13(); | |
483 | } | |
a8be9f80 | 484 | break; |
e78a59f5 | 485 | case 2: |
a8be9f80 | 486 | if (options.protocol & SSH_PROTO_2) { |
e78a59f5 | 487 | enable_compat20(); |
488 | break; | |
489 | } | |
490 | /* FALLTHROUGH */ | |
6ae2364d | 491 | default: |
a8be9f80 | 492 | mismatch = 1; |
493 | break; | |
494 | } | |
495 | chop(server_version_string); | |
a8be9f80 | 496 | debug("Local version string %.200s", server_version_string); |
497 | ||
498 | if (mismatch) { | |
7368a6c8 | 499 | s = "Protocol major versions differ.\n"; |
dc54438a | 500 | (void) atomicio(vwrite, sock_out, s, strlen(s)); |
7368a6c8 | 501 | close(sock_in); |
502 | close(sock_out); | |
bbe88b6d | 503 | logit("Protocol major versions differ for %s: %.200s vs. %.200s", |
a8be9f80 | 504 | get_remote_ipaddr(), |
505 | server_version_string, client_version_string); | |
2362db19 | 506 | cleanup_exit(255); |
7368a6c8 | 507 | } |
a306f2dd | 508 | } |
509 | ||
fa08c86b | 510 | /* Destroy the host and server keys. They will no longer be needed. */ |
a306f2dd | 511 | void |
512 | destroy_sensitive_data(void) | |
513 | { | |
fa08c86b | 514 | int i; |
515 | ||
516 | if (sensitive_data.server_key) { | |
517 | key_free(sensitive_data.server_key); | |
518 | sensitive_data.server_key = NULL; | |
519 | } | |
184eed6a | 520 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 521 | if (sensitive_data.host_keys[i]) { |
522 | key_free(sensitive_data.host_keys[i]); | |
523 | sensitive_data.host_keys[i] = NULL; | |
524 | } | |
525 | } | |
526 | sensitive_data.ssh1_host_key = NULL; | |
00be5382 | 527 | memset(sensitive_data.ssh1_cookie, 0, SSH_SESSION_KEY_LENGTH); |
fa08c86b | 528 | } |
fa08c86b | 529 | |
1853d1ef | 530 | /* Demote private to public keys for network child */ |
531 | void | |
532 | demote_sensitive_data(void) | |
533 | { | |
534 | Key *tmp; | |
535 | int i; | |
536 | ||
537 | if (sensitive_data.server_key) { | |
538 | tmp = key_demote(sensitive_data.server_key); | |
539 | key_free(sensitive_data.server_key); | |
540 | sensitive_data.server_key = tmp; | |
541 | } | |
542 | ||
543 | for (i = 0; i < options.num_host_key_files; i++) { | |
544 | if (sensitive_data.host_keys[i]) { | |
545 | tmp = key_demote(sensitive_data.host_keys[i]); | |
546 | key_free(sensitive_data.host_keys[i]); | |
547 | sensitive_data.host_keys[i] = tmp; | |
548 | if (tmp->type == KEY_RSA1) | |
549 | sensitive_data.ssh1_host_key = tmp; | |
550 | } | |
551 | } | |
552 | ||
553 | /* We do not clear ssh1_host key and cookie. XXX - Okay Niels? */ | |
554 | } | |
555 | ||
51aeb639 | 556 | static void |
1853d1ef | 557 | privsep_preauth_child(void) |
558 | { | |
7fdc56c5 | 559 | u_int32_t rnd[256]; |
6ded293b | 560 | gid_t gidset[1]; |
2ea6de2b | 561 | struct passwd *pw; |
e424e241 | 562 | int i; |
1853d1ef | 563 | |
564 | /* Enable challenge-response authentication for privilege separation */ | |
565 | privsep_challenge_enable(); | |
566 | ||
567 | for (i = 0; i < 256; i++) | |
7fdc56c5 | 568 | rnd[i] = arc4random(); |
569 | RAND_seed(rnd, sizeof(rnd)); | |
1853d1ef | 570 | |
571 | /* Demote the private keys to public keys. */ | |
572 | demote_sensitive_data(); | |
573 | ||
2ea6de2b | 574 | if ((pw = getpwnam(SSH_PRIVSEP_USER)) == NULL) |
cdc4fc39 | 575 | fatal("Privilege separation user %s does not exist", |
576 | SSH_PRIVSEP_USER); | |
2ea6de2b | 577 | memset(pw->pw_passwd, 0, strlen(pw->pw_passwd)); |
578 | endpwent(); | |
579 | ||
343288b8 | 580 | /* Change our root directory */ |
1c352e97 | 581 | if (chroot(_PATH_PRIVSEP_CHROOT_DIR) == -1) |
582 | fatal("chroot(\"%s\"): %s", _PATH_PRIVSEP_CHROOT_DIR, | |
583 | strerror(errno)); | |
1853d1ef | 584 | if (chdir("/") == -1) |
edfb66cb | 585 | fatal("chdir(\"/\"): %s", strerror(errno)); |
762715ce | 586 | |
1853d1ef | 587 | /* Drop our privileges */ |
2ea6de2b | 588 | debug3("privsep user:group %u:%u", (u_int)pw->pw_uid, |
589 | (u_int)pw->pw_gid); | |
87809a1f | 590 | #if 0 |
6ff58a4b | 591 | /* XXX not ready, too heavy after chroot */ |
2ea6de2b | 592 | do_setusercontext(pw); |
87809a1f | 593 | #else |
594 | gidset[0] = pw->pw_gid; | |
87809a1f | 595 | if (setgroups(1, gidset) < 0) |
596 | fatal("setgroups: %.100s", strerror(errno)); | |
597 | permanently_set_uid(pw); | |
598 | #endif | |
1853d1ef | 599 | } |
600 | ||
2362db19 | 601 | static int |
602 | privsep_preauth(Authctxt *authctxt) | |
1853d1ef | 603 | { |
1853d1ef | 604 | int status; |
324bf712 | 605 | pid_t pid; |
1853d1ef | 606 | |
324bf712 | 607 | /* Set up unprivileged child process to deal with network data */ |
b5a28cbc | 608 | pmonitor = monitor_init(); |
324bf712 | 609 | /* Store a pointer to the kex for later rekeying */ |
b5a28cbc | 610 | pmonitor->m_pkex = &xxx_kex; |
324bf712 | 611 | |
612 | pid = fork(); | |
613 | if (pid == -1) { | |
614 | fatal("fork of unprivileged child failed"); | |
615 | } else if (pid != 0) { | |
c457707e | 616 | debug2("Network child is on pid %ld", (long)pid); |
324bf712 | 617 | |
b5a28cbc | 618 | close(pmonitor->m_recvfd); |
a9b33b95 | 619 | pmonitor->m_pid = pid; |
2362db19 | 620 | monitor_child_preauth(authctxt, pmonitor); |
b5a28cbc | 621 | close(pmonitor->m_sendfd); |
324bf712 | 622 | |
623 | /* Sync memory */ | |
b5a28cbc | 624 | monitor_sync(pmonitor); |
324bf712 | 625 | |
626 | /* Wait for the child's exit status */ | |
8c38e88b | 627 | while (waitpid(pid, &status, 0) < 0) |
628 | if (errno != EINTR) | |
629 | break; | |
2362db19 | 630 | return (1); |
324bf712 | 631 | } else { |
632 | /* child */ | |
633 | ||
b5a28cbc | 634 | close(pmonitor->m_sendfd); |
324bf712 | 635 | |
636 | /* Demote the child */ | |
637 | if (getuid() == 0 || geteuid() == 0) | |
638 | privsep_preauth_child(); | |
47c36e5b | 639 | setproctitle("%s", "[net]"); |
324bf712 | 640 | } |
2362db19 | 641 | return (0); |
324bf712 | 642 | } |
643 | ||
644 | static void | |
645 | privsep_postauth(Authctxt *authctxt) | |
646 | { | |
94d8258b | 647 | #ifdef DISABLE_FD_PASSING |
d170feb1 | 648 | if (1) { |
649 | #else | |
1853d1ef | 650 | if (authctxt->pw->pw_uid == 0 || options.use_login) { |
d170feb1 | 651 | #endif |
1853d1ef | 652 | /* File descriptor passing is broken or root login */ |
1853d1ef | 653 | use_privsep = 0; |
ae25711b | 654 | goto skip; |
1853d1ef | 655 | } |
762715ce | 656 | |
1853d1ef | 657 | /* New socket pair */ |
b5a28cbc | 658 | monitor_reinit(pmonitor); |
1853d1ef | 659 | |
b5a28cbc | 660 | pmonitor->m_pid = fork(); |
661 | if (pmonitor->m_pid == -1) | |
1853d1ef | 662 | fatal("fork of unprivileged child failed"); |
b5a28cbc | 663 | else if (pmonitor->m_pid != 0) { |
c457707e | 664 | debug2("User child is on pid %ld", (long)pmonitor->m_pid); |
b5a28cbc | 665 | close(pmonitor->m_recvfd); |
f143ed33 | 666 | buffer_clear(&loginmsg); |
b5a28cbc | 667 | monitor_child_postauth(pmonitor); |
1853d1ef | 668 | |
669 | /* NEVERREACHED */ | |
670 | exit(0); | |
671 | } | |
672 | ||
b5a28cbc | 673 | close(pmonitor->m_sendfd); |
1853d1ef | 674 | |
675 | /* Demote the private keys to public keys. */ | |
676 | demote_sensitive_data(); | |
677 | ||
678 | /* Drop privileges */ | |
679 | do_setusercontext(authctxt->pw); | |
680 | ||
ae25711b | 681 | skip: |
1853d1ef | 682 | /* It is safe now to apply the key state */ |
b5a28cbc | 683 | monitor_apply_keystate(pmonitor); |
07200973 | 684 | |
685 | /* | |
686 | * Tell the packet layer that authentication was successful, since | |
687 | * this information is not part of the key state. | |
688 | */ | |
689 | packet_set_authenticated(); | |
1853d1ef | 690 | } |
691 | ||
396c147e | 692 | static char * |
fa08c86b | 693 | list_hostkey_types(void) |
694 | { | |
3469eac4 | 695 | Buffer b; |
b6c7b7b7 | 696 | const char *p; |
697 | char *ret; | |
fa08c86b | 698 | int i; |
3469eac4 | 699 | |
700 | buffer_init(&b); | |
184eed6a | 701 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 702 | Key *key = sensitive_data.host_keys[i]; |
703 | if (key == NULL) | |
704 | continue; | |
6aacefa7 | 705 | switch (key->type) { |
fa08c86b | 706 | case KEY_RSA: |
707 | case KEY_DSA: | |
3469eac4 | 708 | if (buffer_len(&b) > 0) |
709 | buffer_append(&b, ",", 1); | |
710 | p = key_ssh_name(key); | |
711 | buffer_append(&b, p, strlen(p)); | |
fa08c86b | 712 | break; |
713 | } | |
714 | } | |
3469eac4 | 715 | buffer_append(&b, "\0", 1); |
b6c7b7b7 | 716 | ret = xstrdup(buffer_ptr(&b)); |
3469eac4 | 717 | buffer_free(&b); |
b6c7b7b7 | 718 | debug("list_hostkey_types: %s", ret); |
719 | return ret; | |
fa08c86b | 720 | } |
721 | ||
1853d1ef | 722 | Key * |
fa08c86b | 723 | get_hostkey_by_type(int type) |
724 | { | |
725 | int i; | |
e424e241 | 726 | |
184eed6a | 727 | for (i = 0; i < options.num_host_key_files; i++) { |
fa08c86b | 728 | Key *key = sensitive_data.host_keys[i]; |
729 | if (key != NULL && key->type == type) | |
730 | return key; | |
731 | } | |
732 | return NULL; | |
7368a6c8 | 733 | } |
734 | ||
1853d1ef | 735 | Key * |
736 | get_hostkey_by_index(int ind) | |
737 | { | |
738 | if (ind < 0 || ind >= options.num_host_key_files) | |
739 | return (NULL); | |
740 | return (sensitive_data.host_keys[ind]); | |
741 | } | |
742 | ||
743 | int | |
744 | get_hostkey_index(Key *key) | |
745 | { | |
746 | int i; | |
e424e241 | 747 | |
1853d1ef | 748 | for (i = 0; i < options.num_host_key_files; i++) { |
749 | if (key == sensitive_data.host_keys[i]) | |
750 | return (i); | |
751 | } | |
752 | return (-1); | |
753 | } | |
754 | ||
c345cf9d | 755 | /* |
756 | * returns 1 if connection should be dropped, 0 otherwise. | |
757 | * dropping starts at connection #max_startups_begin with a probability | |
758 | * of (max_startups_rate/100). the probability increases linearly until | |
759 | * all connections are dropped for startups > max_startups | |
760 | */ | |
396c147e | 761 | static int |
c345cf9d | 762 | drop_connection(int startups) |
763 | { | |
1c5eab6f | 764 | int p, r; |
c345cf9d | 765 | |
766 | if (startups < options.max_startups_begin) | |
767 | return 0; | |
768 | if (startups >= options.max_startups) | |
769 | return 1; | |
770 | if (options.max_startups_rate == 100) | |
771 | return 1; | |
772 | ||
773 | p = 100 - options.max_startups_rate; | |
774 | p *= startups - options.max_startups_begin; | |
1c5eab6f | 775 | p /= options.max_startups - options.max_startups_begin; |
c345cf9d | 776 | p += options.max_startups_rate; |
1c5eab6f | 777 | r = arc4random() % 100; |
c345cf9d | 778 | |
e9aec1d4 | 779 | debug("drop_connection: p %d, r %d", p, r); |
c345cf9d | 780 | return (r < p) ? 1 : 0; |
781 | } | |
782 | ||
2717fa0f | 783 | static void |
784 | usage(void) | |
785 | { | |
85ac7a84 | 786 | fprintf(stderr, "%s, %s\n", |
4526e8c2 | 787 | SSH_RELEASE, SSLeay_version(SSLEAY_VERSION)); |
65edde94 | 788 | fprintf(stderr, |
789 | "usage: sshd [-46Ddeiqt] [-b bits] [-f config_file] [-g login_grace_time]\n" | |
790 | " [-h host_key_file] [-k key_gen_time] [-o option] [-p port] [-u len]\n" | |
791 | ); | |
2717fa0f | 792 | exit(1); |
793 | } | |
794 | ||
b9a549d7 | 795 | static void |
796 | send_rexec_state(int fd, Buffer *conf) | |
797 | { | |
798 | Buffer m; | |
799 | ||
800 | debug3("%s: entering fd = %d config len %d", __func__, fd, | |
801 | buffer_len(conf)); | |
802 | ||
803 | /* | |
804 | * Protocol from reexec master to child: | |
805 | * string configuration | |
806 | * u_int ephemeral_key_follows | |
807 | * bignum e (only if ephemeral_key_follows == 1) | |
808 | * bignum n " | |
809 | * bignum d " | |
810 | * bignum iqmp " | |
811 | * bignum p " | |
812 | * bignum q " | |
72f02ae7 | 813 | * string rngseed (only if OpenSSL is not self-seeded) |
b9a549d7 | 814 | */ |
815 | buffer_init(&m); | |
816 | buffer_put_cstring(&m, buffer_ptr(conf)); | |
817 | ||
f2107e97 | 818 | if (sensitive_data.server_key != NULL && |
b9a549d7 | 819 | sensitive_data.server_key->type == KEY_RSA1) { |
820 | buffer_put_int(&m, 1); | |
821 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->e); | |
822 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->n); | |
823 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->d); | |
824 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
825 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->p); | |
826 | buffer_put_bignum(&m, sensitive_data.server_key->rsa->q); | |
827 | } else | |
828 | buffer_put_int(&m, 0); | |
829 | ||
72f02ae7 | 830 | #ifndef OPENSSL_PRNG_ONLY |
831 | rexec_send_rng_seed(&m); | |
832 | #endif | |
833 | ||
b9a549d7 | 834 | if (ssh_msg_send(fd, 0, &m) == -1) |
835 | fatal("%s: ssh_msg_send failed", __func__); | |
836 | ||
837 | buffer_free(&m); | |
838 | ||
839 | debug3("%s: done", __func__); | |
840 | } | |
841 | ||
842 | static void | |
843 | recv_rexec_state(int fd, Buffer *conf) | |
844 | { | |
845 | Buffer m; | |
846 | char *cp; | |
847 | u_int len; | |
848 | ||
849 | debug3("%s: entering fd = %d", __func__, fd); | |
850 | ||
851 | buffer_init(&m); | |
852 | ||
853 | if (ssh_msg_recv(fd, &m) == -1) | |
854 | fatal("%s: ssh_msg_recv failed", __func__); | |
855 | if (buffer_get_char(&m) != 0) | |
856 | fatal("%s: rexec version mismatch", __func__); | |
857 | ||
858 | cp = buffer_get_string(&m, &len); | |
859 | if (conf != NULL) | |
860 | buffer_append(conf, cp, len + 1); | |
861 | xfree(cp); | |
862 | ||
863 | if (buffer_get_int(&m)) { | |
864 | if (sensitive_data.server_key != NULL) | |
865 | key_free(sensitive_data.server_key); | |
866 | sensitive_data.server_key = key_new_private(KEY_RSA1); | |
867 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->e); | |
868 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->n); | |
869 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->d); | |
870 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->iqmp); | |
871 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->p); | |
872 | buffer_get_bignum(&m, sensitive_data.server_key->rsa->q); | |
873 | rsa_generate_additional_parameters( | |
874 | sensitive_data.server_key->rsa); | |
875 | } | |
72f02ae7 | 876 | |
877 | #ifndef OPENSSL_PRNG_ONLY | |
878 | rexec_recv_rng_seed(&m); | |
879 | #endif | |
880 | ||
b9a549d7 | 881 | buffer_free(&m); |
882 | ||
883 | debug3("%s: done", __func__); | |
884 | } | |
885 | ||
5260325f | 886 | /* |
887 | * Main program for the daemon. | |
888 | */ | |
8efc0c15 | 889 | int |
890 | main(int ac, char **av) | |
891 | { | |
5260325f | 892 | extern char *optarg; |
893 | extern int optind; | |
52e3daed | 894 | int opt, j, i, on = 1; |
83529a6b | 895 | int sock_in = -1, sock_out = -1, newsock = -1; |
9da5c3c9 | 896 | pid_t pid; |
48e671d5 | 897 | socklen_t fromlen; |
48e671d5 | 898 | fd_set *fdset; |
899 | struct sockaddr_storage from; | |
5260325f | 900 | const char *remote_ip; |
901 | int remote_port; | |
5260325f | 902 | FILE *f; |
48e671d5 | 903 | struct addrinfo *ai; |
904 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
c5894280 | 905 | char *line; |
48e671d5 | 906 | int listen_sock, maxfd; |
9216f89c | 907 | int startup_p[2] = { -1 , -1 }, config_s[2] = { -1 , -1 }; |
089fbbd2 | 908 | int startups = 0; |
aeaa3d9e | 909 | Key *key; |
2362db19 | 910 | Authctxt *authctxt; |
59c97189 | 911 | int ret, key_used = 0; |
b9a549d7 | 912 | Buffer cfg; |
5260325f | 913 | |
6e879cb4 | 914 | #ifdef HAVE_SECUREWARE |
915 | (void)set_auth_parameters(ac, av); | |
916 | #endif | |
fda04d7d | 917 | __progname = ssh_get_progname(av[0]); |
264dce47 | 918 | init_rng(); |
919 | ||
d0104542 | 920 | /* Save argv. Duplicate so setproctitle emulation doesn't clobber it */ |
4d33e531 | 921 | saved_argc = ac; |
7706b4c7 | 922 | rexec_argc = ac; |
f420d2ba | 923 | saved_argv = xmalloc(sizeof(*saved_argv) * (ac + 1)); |
d0104542 | 924 | for (i = 0; i < ac; i++) |
925 | saved_argv[i] = xstrdup(av[i]); | |
f420d2ba | 926 | saved_argv[i] = NULL; |
d0104542 | 927 | |
928 | #ifndef HAVE_SETPROCTITLE | |
929 | /* Prepare for later setproctitle emulation */ | |
930 | compat_init_setproctitle(ac, av); | |
416c732d | 931 | av = saved_argv; |
d0104542 | 932 | #endif |
5260325f | 933 | |
a4c0faa2 | 934 | if (geteuid() == 0 && setgroups(0, NULL) == -1) |
935 | debug("setgroups(): %.200s", strerror(errno)); | |
936 | ||
fd6168c1 | 937 | /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */ |
938 | sanitise_stdfd(); | |
939 | ||
5260325f | 940 | /* Initialize configuration options to their default values. */ |
941 | initialize_server_options(&options); | |
942 | ||
943 | /* Parse command-line arguments. */ | |
b9a549d7 | 944 | while ((opt = getopt(ac, av, "f:p:b:k:h:g:u:o:dDeiqrtQR46")) != -1) { |
5260325f | 945 | switch (opt) { |
48e671d5 | 946 | case '4': |
31b41ceb | 947 | options.address_family = AF_INET; |
48e671d5 | 948 | break; |
949 | case '6': | |
31b41ceb | 950 | options.address_family = AF_INET6; |
48e671d5 | 951 | break; |
5260325f | 952 | case 'f': |
953 | config_file_name = optarg; | |
954 | break; | |
955 | case 'd': | |
e053cd2c | 956 | if (debug_flag == 0) { |
bcbf86ec | 957 | debug_flag = 1; |
958 | options.log_level = SYSLOG_LEVEL_DEBUG1; | |
e053cd2c | 959 | } else if (options.log_level < SYSLOG_LEVEL_DEBUG3) |
bcbf86ec | 960 | options.log_level++; |
5260325f | 961 | break; |
0b6fbf03 | 962 | case 'D': |
963 | no_daemon_flag = 1; | |
964 | break; | |
ff14faf1 | 965 | case 'e': |
966 | log_stderr = 1; | |
967 | break; | |
5260325f | 968 | case 'i': |
969 | inetd_flag = 1; | |
970 | break; | |
b9a549d7 | 971 | case 'r': |
972 | rexec_flag = 0; | |
973 | break; | |
974 | case 'R': | |
975 | rexeced_flag = 1; | |
976 | inetd_flag = 1; | |
977 | break; | |
5260325f | 978 | case 'Q': |
9bd5b720 | 979 | /* ignored */ |
5260325f | 980 | break; |
981 | case 'q': | |
982 | options.log_level = SYSLOG_LEVEL_QUIET; | |
983 | break; | |
984 | case 'b': | |
3efa8ea9 | 985 | options.server_key_bits = (int)strtonum(optarg, 256, |
986 | 32768, NULL); | |
5260325f | 987 | break; |
988 | case 'p': | |
48e671d5 | 989 | options.ports_from_cmdline = 1; |
bcbf86ec | 990 | if (options.num_ports >= MAX_PORTS) { |
991 | fprintf(stderr, "too many ports.\n"); | |
992 | exit(1); | |
993 | } | |
2d2a2c65 | 994 | options.ports[options.num_ports++] = a2port(optarg); |
995 | if (options.ports[options.num_ports-1] == 0) { | |
996 | fprintf(stderr, "Bad port number.\n"); | |
997 | exit(1); | |
998 | } | |
5260325f | 999 | break; |
1000 | case 'g': | |
e2b1fb42 | 1001 | if ((options.login_grace_time = convtime(optarg)) == -1) { |
1002 | fprintf(stderr, "Invalid login grace time.\n"); | |
1003 | exit(1); | |
1004 | } | |
5260325f | 1005 | break; |
1006 | case 'k': | |
e2b1fb42 | 1007 | if ((options.key_regeneration_time = convtime(optarg)) == -1) { |
1008 | fprintf(stderr, "Invalid key regeneration interval.\n"); | |
1009 | exit(1); | |
1010 | } | |
5260325f | 1011 | break; |
1012 | case 'h': | |
fa08c86b | 1013 | if (options.num_host_key_files >= MAX_HOSTKEYS) { |
1014 | fprintf(stderr, "too many host keys.\n"); | |
1015 | exit(1); | |
1016 | } | |
1017 | options.host_key_files[options.num_host_key_files++] = optarg; | |
5260325f | 1018 | break; |
f87f09aa | 1019 | case 't': |
1020 | test_flag = 1; | |
1021 | break; | |
c345cf9d | 1022 | case 'u': |
3efa8ea9 | 1023 | utmp_len = (u_int)strtonum(optarg, 0, MAXHOSTNAMELEN+1, NULL); |
67f04db1 | 1024 | if (utmp_len > MAXHOSTNAMELEN) { |
1025 | fprintf(stderr, "Invalid utmp length.\n"); | |
1026 | exit(1); | |
1027 | } | |
c345cf9d | 1028 | break; |
2717fa0f | 1029 | case 'o': |
c5894280 | 1030 | line = xstrdup(optarg); |
1031 | if (process_server_config_line(&options, line, | |
2717fa0f | 1032 | "command-line", 0) != 0) |
184eed6a | 1033 | exit(1); |
c5894280 | 1034 | xfree(line); |
2717fa0f | 1035 | break; |
5260325f | 1036 | case '?': |
1037 | default: | |
2717fa0f | 1038 | usage(); |
1039 | break; | |
5260325f | 1040 | } |
1041 | } | |
b9a549d7 | 1042 | if (rexeced_flag || inetd_flag) |
1043 | rexec_flag = 0; | |
1044 | if (rexec_flag && (av[0] == NULL || *av[0] != '/')) | |
1045 | fatal("sshd re-exec requires execution with an absolute path"); | |
1046 | if (rexeced_flag) | |
b250e837 | 1047 | closefrom(REEXEC_MIN_FREE_FD); |
1048 | else | |
1049 | closefrom(REEXEC_DEVCRYPTO_RESERVED_FD); | |
b9a549d7 | 1050 | |
1a92bd7e | 1051 | SSLeay_add_all_algorithms(); |
5260325f | 1052 | |
48e671d5 | 1053 | /* |
1054 | * Force logging to stderr until we have loaded the private host | |
1055 | * key (unless started from inetd) | |
1056 | */ | |
1fe6a48f | 1057 | log_init(__progname, |
980c9344 | 1058 | options.log_level == SYSLOG_LEVEL_NOT_SET ? |
1059 | SYSLOG_LEVEL_INFO : options.log_level, | |
1060 | options.log_facility == SYSLOG_FACILITY_NOT_SET ? | |
1061 | SYSLOG_FACILITY_AUTH : options.log_facility, | |
51efad8c | 1062 | log_stderr || !inetd_flag); |
48e671d5 | 1063 | |
351f44a0 | 1064 | /* |
1065 | * Unset KRB5CCNAME, otherwise the user's session may inherit it from | |
1066 | * root's environment | |
d1cf9a87 | 1067 | */ |
3bfd27d5 | 1068 | if (getenv("KRB5CCNAME") != NULL) |
1069 | unsetenv("KRB5CCNAME"); | |
1070 | ||
ef51930f | 1071 | #ifdef _UNICOS |
e5ba4718 | 1072 | /* Cray can define user privs drop all privs now! |
1a23ac2c | 1073 | * Not needed on PRIV_SU systems! |
1074 | */ | |
1075 | drop_cray_privs(); | |
1076 | #endif | |
1077 | ||
b9a549d7 | 1078 | sensitive_data.server_key = NULL; |
1079 | sensitive_data.ssh1_host_key = NULL; | |
1080 | sensitive_data.have_ssh1_key = 0; | |
1081 | sensitive_data.have_ssh2_key = 0; | |
1082 | ||
1083 | /* Fetch our configuration */ | |
1084 | buffer_init(&cfg); | |
1085 | if (rexeced_flag) | |
b250e837 | 1086 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, &cfg); |
b9a549d7 | 1087 | else |
1088 | load_server_config(config_file_name, &cfg); | |
1089 | ||
1090 | parse_server_config(&options, | |
1091 | rexeced_flag ? "rexec" : config_file_name, &cfg); | |
1092 | ||
1093 | if (!rexec_flag) | |
1094 | buffer_free(&cfg); | |
5260325f | 1095 | |
72f02ae7 | 1096 | seed_rng(); |
1097 | ||
5260325f | 1098 | /* Fill in default values for those options not explicitly set. */ |
1099 | fill_default_server_options(&options); | |
1100 | ||
31b41ceb | 1101 | /* set default channel AF */ |
1102 | channel_set_af(options.address_family); | |
1103 | ||
5260325f | 1104 | /* Check that there are no remaining arguments. */ |
1105 | if (optind < ac) { | |
1106 | fprintf(stderr, "Extra argument %s.\n", av[optind]); | |
1107 | exit(1); | |
8efc0c15 | 1108 | } |
5260325f | 1109 | |
4526e8c2 | 1110 | debug("sshd version %.100s", SSH_RELEASE); |
5260325f | 1111 | |
fa08c86b | 1112 | /* load private host keys */ |
52e3daed | 1113 | sensitive_data.host_keys = xcalloc(options.num_host_key_files, |
343288b8 | 1114 | sizeof(Key *)); |
184eed6a | 1115 | for (i = 0; i < options.num_host_key_files; i++) |
1e3b8b07 | 1116 | sensitive_data.host_keys[i] = NULL; |
a306f2dd | 1117 | |
184eed6a | 1118 | for (i = 0; i < options.num_host_key_files; i++) { |
aeaa3d9e | 1119 | key = key_load_private(options.host_key_files[i], "", NULL); |
1120 | sensitive_data.host_keys[i] = key; | |
fa08c86b | 1121 | if (key == NULL) { |
58cfa257 | 1122 | error("Could not load host key: %s", |
1123 | options.host_key_files[i]); | |
aeaa3d9e | 1124 | sensitive_data.host_keys[i] = NULL; |
fa08c86b | 1125 | continue; |
a306f2dd | 1126 | } |
6aacefa7 | 1127 | switch (key->type) { |
fa08c86b | 1128 | case KEY_RSA1: |
1129 | sensitive_data.ssh1_host_key = key; | |
1130 | sensitive_data.have_ssh1_key = 1; | |
1131 | break; | |
1132 | case KEY_RSA: | |
1133 | case KEY_DSA: | |
1134 | sensitive_data.have_ssh2_key = 1; | |
1135 | break; | |
a306f2dd | 1136 | } |
aeaa3d9e | 1137 | debug("private host key: #%d type %d %s", i, key->type, |
1138 | key_type(key)); | |
fa08c86b | 1139 | } |
1140 | if ((options.protocol & SSH_PROTO_1) && !sensitive_data.have_ssh1_key) { | |
bbe88b6d | 1141 | logit("Disabling protocol version 1. Could not load host key"); |
fa08c86b | 1142 | options.protocol &= ~SSH_PROTO_1; |
1143 | } | |
1144 | if ((options.protocol & SSH_PROTO_2) && !sensitive_data.have_ssh2_key) { | |
bbe88b6d | 1145 | logit("Disabling protocol version 2. Could not load host key"); |
fa08c86b | 1146 | options.protocol &= ~SSH_PROTO_2; |
a306f2dd | 1147 | } |
6a416424 | 1148 | if (!(options.protocol & (SSH_PROTO_1|SSH_PROTO_2))) { |
bbe88b6d | 1149 | logit("sshd: no hostkeys available -- exiting."); |
5260325f | 1150 | exit(1); |
1151 | } | |
5260325f | 1152 | |
a306f2dd | 1153 | /* Check certain values for sanity. */ |
1154 | if (options.protocol & SSH_PROTO_1) { | |
1155 | if (options.server_key_bits < 512 || | |
1156 | options.server_key_bits > 32768) { | |
1157 | fprintf(stderr, "Bad server key size.\n"); | |
1158 | exit(1); | |
1159 | } | |
1160 | /* | |
1161 | * Check that server and host key lengths differ sufficiently. This | |
1162 | * is necessary to make double encryption work with rsaref. Oh, I | |
1163 | * hate software patents. I dont know if this can go? Niels | |
1164 | */ | |
1165 | if (options.server_key_bits > | |
e424e241 | 1166 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) - |
1167 | SSH_KEY_BITS_RESERVED && options.server_key_bits < | |
1168 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + | |
1169 | SSH_KEY_BITS_RESERVED) { | |
a306f2dd | 1170 | options.server_key_bits = |
e424e241 | 1171 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1172 | SSH_KEY_BITS_RESERVED; | |
a306f2dd | 1173 | debug("Forcing server key to %d bits to make it differ from host key.", |
1174 | options.server_key_bits); | |
1175 | } | |
1176 | } | |
1177 | ||
3cc54fbb | 1178 | if (use_privsep) { |
3cc54fbb | 1179 | struct stat st; |
1180 | ||
3efa8ea9 | 1181 | if (getpwnam(SSH_PRIVSEP_USER) == NULL) |
3cc54fbb | 1182 | fatal("Privilege separation user %s does not exist", |
1183 | SSH_PRIVSEP_USER); | |
1184 | if ((stat(_PATH_PRIVSEP_CHROOT_DIR, &st) == -1) || | |
1185 | (S_ISDIR(st.st_mode) == 0)) | |
1186 | fatal("Missing privilege separation directory: %s", | |
1187 | _PATH_PRIVSEP_CHROOT_DIR); | |
b9b82dab | 1188 | |
1189 | #ifdef HAVE_CYGWIN | |
1190 | if (check_ntsec(_PATH_PRIVSEP_CHROOT_DIR) && | |
1191 | (st.st_uid != getuid () || | |
1192 | (st.st_mode & (S_IWGRP|S_IWOTH)) != 0)) | |
1193 | #else | |
a56313d7 | 1194 | if (st.st_uid != 0 || (st.st_mode & (S_IWGRP|S_IWOTH)) != 0) |
b9b82dab | 1195 | #endif |
5f021474 | 1196 | fatal("%s must be owned by root and not group or " |
1197 | "world-writable.", _PATH_PRIVSEP_CHROOT_DIR); | |
3cc54fbb | 1198 | } |
1199 | ||
f87f09aa | 1200 | /* Configuration looks good, so exit if in test mode. */ |
1201 | if (test_flag) | |
1202 | exit(0); | |
1203 | ||
018a5ea3 | 1204 | /* |
1205 | * Clear out any supplemental groups we may have inherited. This | |
1206 | * prevents inadvertent creation of files with bad modes (in the | |
aff51935 | 1207 | * portable version at least, it's certainly possible for PAM |
1208 | * to create a file, and we can't control the code in every | |
018a5ea3 | 1209 | * module which might be used). |
1210 | */ | |
1211 | if (setgroups(0, NULL) < 0) | |
1212 | debug("setgroups() failed: %.200s", strerror(errno)); | |
1213 | ||
b9a549d7 | 1214 | if (rexec_flag) { |
52e3daed | 1215 | rexec_argv = xcalloc(rexec_argc + 2, sizeof(char *)); |
b9a549d7 | 1216 | for (i = 0; i < rexec_argc; i++) { |
1217 | debug("rexec_argv[%d]='%s'", i, saved_argv[i]); | |
1218 | rexec_argv[i] = saved_argv[i]; | |
1219 | } | |
1220 | rexec_argv[rexec_argc] = "-R"; | |
1221 | rexec_argv[rexec_argc + 1] = NULL; | |
1222 | } | |
1223 | ||
a306f2dd | 1224 | /* Initialize the log (it is reinitialized below in case we forked). */ |
25c31d49 | 1225 | if (debug_flag && (!inetd_flag || rexeced_flag)) |
5260325f | 1226 | log_stderr = 1; |
1fe6a48f | 1227 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1228 | |
a306f2dd | 1229 | /* |
1230 | * If not in debugging mode, and not started from inetd, disconnect | |
1231 | * from the controlling terminal, and fork. The original process | |
1232 | * exits. | |
1233 | */ | |
0b6fbf03 | 1234 | if (!(debug_flag || inetd_flag || no_daemon_flag)) { |
8efc0c15 | 1235 | #ifdef TIOCNOTTY |
5260325f | 1236 | int fd; |
8efc0c15 | 1237 | #endif /* TIOCNOTTY */ |
5260325f | 1238 | if (daemon(0, 0) < 0) |
1239 | fatal("daemon() failed: %.200s", strerror(errno)); | |
1240 | ||
1241 | /* Disconnect from the controlling tty. */ | |
8efc0c15 | 1242 | #ifdef TIOCNOTTY |
5ca51e19 | 1243 | fd = open(_PATH_TTY, O_RDWR | O_NOCTTY); |
5260325f | 1244 | if (fd >= 0) { |
1245 | (void) ioctl(fd, TIOCNOTTY, NULL); | |
1246 | close(fd); | |
1247 | } | |
8efc0c15 | 1248 | #endif /* TIOCNOTTY */ |
8efc0c15 | 1249 | } |
5260325f | 1250 | /* Reinitialize the log (because of the fork above). */ |
1fe6a48f | 1251 | log_init(__progname, options.log_level, options.log_facility, log_stderr); |
5260325f | 1252 | |
5260325f | 1253 | /* Initialize the random number generator. */ |
1254 | arc4random_stir(); | |
1255 | ||
1256 | /* Chdir to the root directory so that the current disk can be | |
1257 | unmounted if desired. */ | |
1258 | chdir("/"); | |
184eed6a | 1259 | |
1d3c30db | 1260 | /* ignore SIGPIPE */ |
1261 | signal(SIGPIPE, SIG_IGN); | |
5260325f | 1262 | |
5260325f | 1263 | /* Start listening for a socket, unless started from inetd. */ |
1264 | if (inetd_flag) { | |
b9a549d7 | 1265 | int fd; |
1266 | ||
4c8722d9 | 1267 | startup_pipe = -1; |
b9a549d7 | 1268 | if (rexeced_flag) { |
b250e837 | 1269 | close(REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1270 | sock_in = sock_out = dup(STDIN_FILENO); |
1271 | if (!debug_flag) { | |
b250e837 | 1272 | startup_pipe = dup(REEXEC_STARTUP_PIPE_FD); |
1273 | close(REEXEC_STARTUP_PIPE_FD); | |
b9a549d7 | 1274 | } |
1275 | } else { | |
1276 | sock_in = dup(STDIN_FILENO); | |
1277 | sock_out = dup(STDOUT_FILENO); | |
1278 | } | |
a306f2dd | 1279 | /* |
1280 | * We intentionally do not close the descriptors 0, 1, and 2 | |
b9a549d7 | 1281 | * as our code for setting the descriptors won't work if |
a306f2dd | 1282 | * ttyfd happens to be one of those. |
1283 | */ | |
b9a549d7 | 1284 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1285 | dup2(fd, STDIN_FILENO); | |
1286 | dup2(fd, STDOUT_FILENO); | |
1287 | if (fd > STDOUT_FILENO) | |
1288 | close(fd); | |
1289 | } | |
5260325f | 1290 | debug("inetd sockets after dupping: %d, %d", sock_in, sock_out); |
b9a549d7 | 1291 | if ((options.protocol & SSH_PROTO_1) && |
1292 | sensitive_data.server_key == NULL) | |
cb7bd922 | 1293 | generate_ephemeral_server_key(); |
5260325f | 1294 | } else { |
48e671d5 | 1295 | for (ai = options.listen_addrs; ai; ai = ai->ai_next) { |
1296 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
1297 | continue; | |
1298 | if (num_listen_socks >= MAX_LISTEN_SOCKS) | |
1299 | fatal("Too many listen sockets. " | |
1300 | "Enlarge MAX_LISTEN_SOCKS"); | |
945a9853 | 1301 | if ((ret = getnameinfo(ai->ai_addr, ai->ai_addrlen, |
48e671d5 | 1302 | ntop, sizeof(ntop), strport, sizeof(strport), |
945a9853 | 1303 | NI_NUMERICHOST|NI_NUMERICSERV)) != 0) { |
1304 | error("getnameinfo failed: %.100s", | |
1305 | (ret != EAI_SYSTEM) ? gai_strerror(ret) : | |
1306 | strerror(errno)); | |
48e671d5 | 1307 | continue; |
1308 | } | |
1309 | /* Create socket for listening. */ | |
3e131a6d | 1310 | listen_sock = socket(ai->ai_family, ai->ai_socktype, |
1311 | ai->ai_protocol); | |
48e671d5 | 1312 | if (listen_sock < 0) { |
1313 | /* kernel may not support ipv6 */ | |
1314 | verbose("socket: %.100s", strerror(errno)); | |
1315 | continue; | |
1316 | } | |
170694d7 | 1317 | if (set_nonblock(listen_sock) == -1) { |
a666e3b1 | 1318 | close(listen_sock); |
1319 | continue; | |
1320 | } | |
48e671d5 | 1321 | /* |
facfd613 | 1322 | * Set socket options. |
1323 | * Allow local port reuse in TIME_WAIT. | |
48e671d5 | 1324 | */ |
facfd613 | 1325 | if (setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, |
1326 | &on, sizeof(on)) == -1) | |
1327 | error("setsockopt SO_REUSEADDR: %s", strerror(errno)); | |
48e671d5 | 1328 | |
1329 | debug("Bind to port %s on %s.", strport, ntop); | |
1330 | ||
1331 | /* Bind the socket to the desired port. */ | |
32ced054 | 1332 | if (bind(listen_sock, ai->ai_addr, ai->ai_addrlen) < 0) { |
1333 | if (!ai->ai_next) | |
1334 | error("Bind to port %s on %s failed: %.200s.", | |
1335 | strport, ntop, strerror(errno)); | |
48e671d5 | 1336 | close(listen_sock); |
1337 | continue; | |
1338 | } | |
1339 | listen_socks[num_listen_socks] = listen_sock; | |
1340 | num_listen_socks++; | |
1341 | ||
1342 | /* Start listening on the port. */ | |
fce39749 | 1343 | if (listen(listen_sock, SSH_LISTEN_BACKLOG) < 0) |
9f513268 | 1344 | fatal("listen on [%s]:%s: %.100s", |
1345 | ntop, strport, strerror(errno)); | |
1346 | logit("Server listening on %s port %s.", ntop, strport); | |
5260325f | 1347 | } |
48e671d5 | 1348 | freeaddrinfo(options.listen_addrs); |
1349 | ||
1350 | if (!num_listen_socks) | |
1351 | fatal("Cannot bind any address."); | |
1352 | ||
3aca00a3 | 1353 | if (options.protocol & SSH_PROTO_1) |
1354 | generate_ephemeral_server_key(); | |
1355 | ||
1356 | /* | |
1357 | * Arrange to restart on SIGHUP. The handler needs | |
1358 | * listen_sock. | |
1359 | */ | |
1360 | signal(SIGHUP, sighup_handler); | |
1361 | ||
1362 | signal(SIGTERM, sigterm_handler); | |
1363 | signal(SIGQUIT, sigterm_handler); | |
1364 | ||
1365 | /* Arrange SIGCHLD to be caught. */ | |
1366 | signal(SIGCHLD, main_sigchld_handler); | |
1367 | ||
1368 | /* Write out the pid file after the sigterm handler is setup */ | |
5260325f | 1369 | if (!debug_flag) { |
aa3378df | 1370 | /* |
97fb6912 | 1371 | * Record our pid in /var/run/sshd.pid to make it |
1372 | * easier to kill the correct sshd. We don't want to | |
1373 | * do this before the bind above because the bind will | |
aa3378df | 1374 | * fail if there already is a daemon, and this will |
1375 | * overwrite any old pid in the file. | |
1376 | */ | |
3c62e7eb | 1377 | f = fopen(options.pid_file, "wb"); |
71b9ced0 | 1378 | if (f == NULL) { |
1379 | error("Couldn't create pid file \"%s\": %s", | |
1380 | options.pid_file, strerror(errno)); | |
1381 | } else { | |
c457707e | 1382 | fprintf(f, "%ld\n", (long) getpid()); |
5260325f | 1383 | fclose(f); |
1384 | } | |
8efc0c15 | 1385 | } |
5260325f | 1386 | |
48e671d5 | 1387 | /* setup fd set for listen */ |
089fbbd2 | 1388 | fdset = NULL; |
48e671d5 | 1389 | maxfd = 0; |
1390 | for (i = 0; i < num_listen_socks; i++) | |
1391 | if (listen_socks[i] > maxfd) | |
1392 | maxfd = listen_socks[i]; | |
089fbbd2 | 1393 | /* pipes connected to unauthenticated childs */ |
52e3daed | 1394 | startup_pipes = xcalloc(options.max_startups, sizeof(int)); |
089fbbd2 | 1395 | for (i = 0; i < options.max_startups; i++) |
1396 | startup_pipes[i] = -1; | |
48e671d5 | 1397 | |
aa3378df | 1398 | /* |
1399 | * Stay listening for connections until the system crashes or | |
1400 | * the daemon is killed with a signal. | |
1401 | */ | |
5260325f | 1402 | for (;;) { |
1403 | if (received_sighup) | |
1404 | sighup_restart(); | |
089fbbd2 | 1405 | if (fdset != NULL) |
1406 | xfree(fdset); | |
52e3daed | 1407 | fdset = (fd_set *)xcalloc(howmany(maxfd + 1, NFDBITS), |
1408 | sizeof(fd_mask)); | |
089fbbd2 | 1409 | |
48e671d5 | 1410 | for (i = 0; i < num_listen_socks; i++) |
1411 | FD_SET(listen_socks[i], fdset); | |
089fbbd2 | 1412 | for (i = 0; i < options.max_startups; i++) |
1413 | if (startup_pipes[i] != -1) | |
1414 | FD_SET(startup_pipes[i], fdset); | |
1415 | ||
1416 | /* Wait in select until there is a connection. */ | |
59c97189 | 1417 | ret = select(maxfd+1, fdset, NULL, NULL, NULL); |
1418 | if (ret < 0 && errno != EINTR) | |
1419 | error("select: %.100s", strerror(errno)); | |
c9130033 | 1420 | if (received_sigterm) { |
bbe88b6d | 1421 | logit("Received signal %d; terminating.", |
010f9726 | 1422 | (int) received_sigterm); |
c9130033 | 1423 | close_listen_socks(); |
1424 | unlink(options.pid_file); | |
1425 | exit(255); | |
1426 | } | |
59c97189 | 1427 | if (key_used && key_do_regen) { |
cb7bd922 | 1428 | generate_ephemeral_server_key(); |
59c97189 | 1429 | key_used = 0; |
1430 | key_do_regen = 0; | |
48e671d5 | 1431 | } |
59c97189 | 1432 | if (ret < 0) |
1433 | continue; | |
1434 | ||
089fbbd2 | 1435 | for (i = 0; i < options.max_startups; i++) |
1436 | if (startup_pipes[i] != -1 && | |
1437 | FD_ISSET(startup_pipes[i], fdset)) { | |
1438 | /* | |
1439 | * the read end of the pipe is ready | |
1440 | * if the child has closed the pipe | |
8abcdba4 | 1441 | * after successful authentication |
089fbbd2 | 1442 | * or if the child has died |
1443 | */ | |
1444 | close(startup_pipes[i]); | |
1445 | startup_pipes[i] = -1; | |
1446 | startups--; | |
1447 | } | |
48e671d5 | 1448 | for (i = 0; i < num_listen_socks; i++) { |
1449 | if (!FD_ISSET(listen_socks[i], fdset)) | |
5260325f | 1450 | continue; |
089fbbd2 | 1451 | fromlen = sizeof(from); |
3efa8ea9 | 1452 | newsock = accept(listen_socks[i], |
1453 | (struct sockaddr *)&from, &fromlen); | |
089fbbd2 | 1454 | if (newsock < 0) { |
1455 | if (errno != EINTR && errno != EWOULDBLOCK) | |
1456 | error("accept: %.100s", strerror(errno)); | |
1457 | continue; | |
1458 | } | |
170694d7 | 1459 | if (unset_nonblock(newsock) == -1) { |
a666e3b1 | 1460 | close(newsock); |
1461 | continue; | |
1462 | } | |
c345cf9d | 1463 | if (drop_connection(startups) == 1) { |
1464 | debug("drop connection #%d", startups); | |
089fbbd2 | 1465 | close(newsock); |
1466 | continue; | |
1467 | } | |
1468 | if (pipe(startup_p) == -1) { | |
1469 | close(newsock); | |
1470 | continue; | |
1471 | } | |
1472 | ||
b9a549d7 | 1473 | if (rexec_flag && socketpair(AF_UNIX, |
1474 | SOCK_STREAM, 0, config_s) == -1) { | |
1475 | error("reexec socketpair: %s", | |
1476 | strerror(errno)); | |
1477 | close(newsock); | |
1478 | close(startup_p[0]); | |
1479 | close(startup_p[1]); | |
1480 | continue; | |
1481 | } | |
1482 | ||
089fbbd2 | 1483 | for (j = 0; j < options.max_startups; j++) |
1484 | if (startup_pipes[j] == -1) { | |
1485 | startup_pipes[j] = startup_p[0]; | |
1486 | if (maxfd < startup_p[0]) | |
1487 | maxfd = startup_p[0]; | |
1488 | startups++; | |
1489 | break; | |
1490 | } | |
2b87da3b | 1491 | |
aa3378df | 1492 | /* |
089fbbd2 | 1493 | * Got connection. Fork a child to handle it, unless |
1494 | * we are in debugging mode. | |
aa3378df | 1495 | */ |
089fbbd2 | 1496 | if (debug_flag) { |
aa3378df | 1497 | /* |
089fbbd2 | 1498 | * In debugging mode. Close the listening |
1499 | * socket, and start processing the | |
1500 | * connection without forking. | |
aa3378df | 1501 | */ |
089fbbd2 | 1502 | debug("Server will not fork when running in debugging mode."); |
48e671d5 | 1503 | close_listen_socks(); |
5260325f | 1504 | sock_in = newsock; |
1505 | sock_out = newsock; | |
b9a549d7 | 1506 | close(startup_p[0]); |
1507 | close(startup_p[1]); | |
5540ea9b | 1508 | startup_pipe = -1; |
3f7a7e4a | 1509 | pid = getpid(); |
b9a549d7 | 1510 | if (rexec_flag) { |
1511 | send_rexec_state(config_s[0], | |
1512 | &cfg); | |
1513 | close(config_s[0]); | |
1514 | } | |
5260325f | 1515 | break; |
089fbbd2 | 1516 | } else { |
1517 | /* | |
1518 | * Normal production daemon. Fork, and have | |
1519 | * the child process the connection. The | |
1520 | * parent continues listening. | |
1521 | */ | |
1522 | if ((pid = fork()) == 0) { | |
1523 | /* | |
3efa8ea9 | 1524 | * Child. Close the listening and |
1525 | * max_startup sockets. Start using | |
1526 | * the accepted socket. Reinitialize | |
1527 | * logging (since our pid has changed). | |
1528 | * We break out of the loop to handle | |
089fbbd2 | 1529 | * the connection. |
1530 | */ | |
1531 | startup_pipe = startup_p[1]; | |
7ace8c3b | 1532 | close_startup_pipes(); |
089fbbd2 | 1533 | close_listen_socks(); |
1534 | sock_in = newsock; | |
1535 | sock_out = newsock; | |
3efa8ea9 | 1536 | log_init(__progname, |
1537 | options.log_level, | |
1538 | options.log_facility, | |
1539 | log_stderr); | |
9216f89c | 1540 | if (rexec_flag) |
1541 | close(config_s[0]); | |
089fbbd2 | 1542 | break; |
1543 | } | |
5260325f | 1544 | } |
5260325f | 1545 | |
089fbbd2 | 1546 | /* Parent. Stay in the loop. */ |
1547 | if (pid < 0) | |
1548 | error("fork: %.100s", strerror(errno)); | |
1549 | else | |
c457707e | 1550 | debug("Forked child %ld.", (long)pid); |
5260325f | 1551 | |
089fbbd2 | 1552 | close(startup_p[1]); |
5260325f | 1553 | |
b9a549d7 | 1554 | if (rexec_flag) { |
1555 | send_rexec_state(config_s[0], &cfg); | |
1556 | close(config_s[0]); | |
1557 | close(config_s[1]); | |
1558 | } | |
1559 | ||
3efa8ea9 | 1560 | /* |
1561 | * Mark that the key has been used (it | |
1562 | * was "given" to the child). | |
1563 | */ | |
59c97189 | 1564 | if ((options.protocol & SSH_PROTO_1) && |
1565 | key_used == 0) { | |
1566 | /* Schedule server key regeneration alarm. */ | |
f00d1f78 | 1567 | signal(SIGALRM, key_regeneration_alarm); |
59c97189 | 1568 | alarm(options.key_regeneration_time); |
1569 | key_used = 1; | |
1570 | } | |
5260325f | 1571 | |
089fbbd2 | 1572 | arc4random_stir(); |
089fbbd2 | 1573 | close(newsock); |
1574 | } | |
48e671d5 | 1575 | /* child process check (or debug mode) */ |
1576 | if (num_listen_socks < 0) | |
1577 | break; | |
5260325f | 1578 | } |
1579 | } | |
8efc0c15 | 1580 | |
5260325f | 1581 | /* This is the child processing a new connection. */ |
cc120685 | 1582 | setproctitle("%s", "[accepted]"); |
5260325f | 1583 | |
8b758bd2 | 1584 | /* |
1585 | * Create a new session and process group since the 4.4BSD | |
1586 | * setlogin() affects the entire process group. We don't | |
1587 | * want the child to be able to affect the parent. | |
1588 | */ | |
1589 | #if !defined(SSHD_ACQUIRES_CTTY) | |
1590 | /* | |
1591 | * If setsid is called, on some platforms sshd will later acquire a | |
1592 | * controlling terminal which will result in "could not set | |
1593 | * controlling tty" errors. | |
1594 | */ | |
1595 | if (!debug_flag && !inetd_flag && setsid() < 0) | |
1596 | error("setsid: %.100s", strerror(errno)); | |
1597 | #endif | |
1598 | ||
b9a549d7 | 1599 | if (rexec_flag) { |
1600 | int fd; | |
1601 | ||
b250e837 | 1602 | debug("rexec start in %d out %d newsock %d pipe %d sock %d", |
1603 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1604 | dup2(newsock, STDIN_FILENO); |
1605 | dup2(STDIN_FILENO, STDOUT_FILENO); | |
1606 | if (startup_pipe == -1) | |
b250e837 | 1607 | close(REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1608 | else |
b250e837 | 1609 | dup2(startup_pipe, REEXEC_STARTUP_PIPE_FD); |
b9a549d7 | 1610 | |
b250e837 | 1611 | dup2(config_s[1], REEXEC_CONFIG_PASS_FD); |
b9a549d7 | 1612 | close(config_s[1]); |
ad148c04 | 1613 | if (startup_pipe != -1) |
1614 | close(startup_pipe); | |
b250e837 | 1615 | |
b9a549d7 | 1616 | execv(rexec_argv[0], rexec_argv); |
1617 | ||
1618 | /* Reexec has failed, fall back and continue */ | |
1619 | error("rexec of %s failed: %s", rexec_argv[0], strerror(errno)); | |
b250e837 | 1620 | recv_rexec_state(REEXEC_CONFIG_PASS_FD, NULL); |
b9a549d7 | 1621 | log_init(__progname, options.log_level, |
1622 | options.log_facility, log_stderr); | |
1623 | ||
1624 | /* Clean up fds */ | |
b250e837 | 1625 | startup_pipe = REEXEC_STARTUP_PIPE_FD; |
b9a549d7 | 1626 | close(config_s[1]); |
b250e837 | 1627 | close(REEXEC_CONFIG_PASS_FD); |
1628 | newsock = sock_out = sock_in = dup(STDIN_FILENO); | |
b9a549d7 | 1629 | if ((fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) { |
1630 | dup2(fd, STDIN_FILENO); | |
1631 | dup2(fd, STDOUT_FILENO); | |
1632 | if (fd > STDERR_FILENO) | |
1633 | close(fd); | |
1634 | } | |
b250e837 | 1635 | debug("rexec cleanup in %d out %d newsock %d pipe %d sock %d", |
1636 | sock_in, sock_out, newsock, startup_pipe, config_s[0]); | |
b9a549d7 | 1637 | } |
1638 | ||
aa3378df | 1639 | /* |
1640 | * Disable the key regeneration alarm. We will not regenerate the | |
1641 | * key since we are no longer in a position to give it to anyone. We | |
1642 | * will not restart on SIGHUP since it no longer makes sense. | |
1643 | */ | |
5260325f | 1644 | alarm(0); |
1645 | signal(SIGALRM, SIG_DFL); | |
1646 | signal(SIGHUP, SIG_DFL); | |
1647 | signal(SIGTERM, SIG_DFL); | |
1648 | signal(SIGQUIT, SIG_DFL); | |
1649 | signal(SIGCHLD, SIG_DFL); | |
9aaf9be4 | 1650 | signal(SIGINT, SIG_DFL); |
5260325f | 1651 | |
aa3378df | 1652 | /* |
1653 | * Register our connection. This turns encryption off because we do | |
1654 | * not have a key. | |
1655 | */ | |
5260325f | 1656 | packet_set_connection(sock_in, sock_out); |
07200973 | 1657 | packet_set_server(); |
5260325f | 1658 | |
7c3bc5a2 | 1659 | /* Set SO_KEEPALIVE if requested. */ |
1660 | if (options.tcp_keep_alive && packet_connection_is_on_socket() && | |
1661 | setsockopt(sock_in, SOL_SOCKET, SO_KEEPALIVE, &on, sizeof(on)) < 0) | |
1662 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
1663 | ||
29798ed0 | 1664 | if ((remote_port = get_remote_port()) < 0) { |
1665 | debug("get_remote_port failed"); | |
1666 | cleanup_exit(255); | |
1667 | } | |
3a85986d | 1668 | |
1669 | /* | |
1670 | * We use get_canonical_hostname with usedns = 0 instead of | |
1671 | * get_remote_ipaddr here so IP options will be checked. | |
1672 | */ | |
1673 | remote_ip = get_canonical_hostname(0); | |
5260325f | 1674 | |
6039eeef | 1675 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 1676 | audit_connection_from(remote_ip, remote_port); |
1677 | #endif | |
5260325f | 1678 | #ifdef LIBWRAP |
ac28afd8 | 1679 | /* Check whether logins are denied from this host. */ |
33e5359c | 1680 | if (packet_connection_is_on_socket()) { |
5260325f | 1681 | struct request_info req; |
8efc0c15 | 1682 | |
8fbc356d | 1683 | request_init(&req, RQ_DAEMON, __progname, RQ_FILE, sock_in, 0); |
5260325f | 1684 | fromhost(&req); |
8efc0c15 | 1685 | |
5260325f | 1686 | if (!hosts_access(&req)) { |
ac28afd8 | 1687 | debug("Connection refused by tcp wrapper"); |
563834bb | 1688 | refuse(&req); |
ac28afd8 | 1689 | /* NOTREACHED */ |
1690 | fatal("libwrap refuse returns"); | |
5260325f | 1691 | } |
8efc0c15 | 1692 | } |
48e671d5 | 1693 | #endif /* LIBWRAP */ |
ac28afd8 | 1694 | |
5260325f | 1695 | /* Log the connection. */ |
1696 | verbose("Connection from %.500s port %d", remote_ip, remote_port); | |
8efc0c15 | 1697 | |
aa3378df | 1698 | /* |
7b9b0103 | 1699 | * We don't want to listen forever unless the other side |
aa3378df | 1700 | * successfully authenticates itself. So we set up an alarm which is |
1701 | * cleared after successful authentication. A limit of zero | |
7b9b0103 | 1702 | * indicates no limit. Note that we don't set the alarm in debugging |
aa3378df | 1703 | * mode; it is just annoying to have the server exit just when you |
1704 | * are about to discover the bug. | |
1705 | */ | |
f00d1f78 | 1706 | signal(SIGALRM, grace_alarm_handler); |
5260325f | 1707 | if (!debug_flag) |
1708 | alarm(options.login_grace_time); | |
1709 | ||
7368a6c8 | 1710 | sshd_exchange_identification(sock_in, sock_out); |
0598d99d | 1711 | |
5260325f | 1712 | packet_set_nonblocking(); |
1713 | ||
2362db19 | 1714 | /* allocate authentication context */ |
52e3daed | 1715 | authctxt = xcalloc(1, sizeof(*authctxt)); |
2362db19 | 1716 | |
1b394137 | 1717 | authctxt->loginmsg = &loginmsg; |
1718 | ||
2362db19 | 1719 | /* XXX global for cleanup, access from other modules */ |
1720 | the_authctxt = authctxt; | |
1721 | ||
022487ce | 1722 | /* prepare buffer to collect messages to display to user after login */ |
1723 | buffer_init(&loginmsg); | |
1724 | ||
324bf712 | 1725 | if (use_privsep) |
2362db19 | 1726 | if (privsep_preauth(authctxt) == 1) |
324bf712 | 1727 | goto authenticated; |
1853d1ef | 1728 | |
7b2ea3a1 | 1729 | /* perform the key exchange */ |
7b2ea3a1 | 1730 | /* authenticate user and start session */ |
e78a59f5 | 1731 | if (compat20) { |
1732 | do_ssh2_kex(); | |
2362db19 | 1733 | do_authentication2(authctxt); |
e78a59f5 | 1734 | } else { |
1735 | do_ssh1_kex(); | |
2362db19 | 1736 | do_authentication(authctxt); |
e78a59f5 | 1737 | } |
324bf712 | 1738 | /* |
1739 | * If we use privilege separation, the unprivileged child transfers | |
1740 | * the current keystate and exits | |
1741 | */ | |
1742 | if (use_privsep) { | |
b5a28cbc | 1743 | mm_send_keystate(pmonitor); |
1853d1ef | 1744 | exit(0); |
324bf712 | 1745 | } |
1853d1ef | 1746 | |
1747 | authenticated: | |
678143bd | 1748 | /* |
1749 | * Cancel the alarm we set to limit the time taken for | |
1750 | * authentication. | |
1751 | */ | |
1752 | alarm(0); | |
1753 | signal(SIGALRM, SIG_DFL); | |
1754 | if (startup_pipe != -1) { | |
1755 | close(startup_pipe); | |
1756 | startup_pipe = -1; | |
1757 | } | |
1758 | ||
6039eeef | 1759 | #ifdef SSH_AUDIT_EVENTS |
1760 | audit_event(SSH_AUTH_SUCCESS); | |
c00e4d75 | 1761 | #endif |
1762 | ||
762715ce | 1763 | /* |
1853d1ef | 1764 | * In privilege separation, we fork another child and prepare |
1765 | * file descriptor passing. | |
1766 | */ | |
1767 | if (use_privsep) { | |
324bf712 | 1768 | privsep_postauth(authctxt); |
1769 | /* the monitor process [priv] will not return */ | |
1853d1ef | 1770 | if (!compat20) |
1771 | destroy_sensitive_data(); | |
1772 | } | |
1b34c1b3 | 1773 | |
2362db19 | 1774 | /* Start session. */ |
1b34c1b3 | 1775 | do_authenticated(authctxt); |
1776 | ||
63284fbb | 1777 | /* The connection has been terminated. */ |
1778 | verbose("Closing connection to %.100s", remote_ip); | |
8efc0c15 | 1779 | |
d94aa2ae | 1780 | #ifdef USE_PAM |
7fceb20d | 1781 | if (options.use_pam) |
1782 | finish_pam(); | |
d94aa2ae | 1783 | #endif /* USE_PAM */ |
8efc0c15 | 1784 | |
2b0c0925 | 1785 | #ifdef SSH_AUDIT_EVENTS |
1786 | PRIVSEP(audit_event(SSH_CONNECTION_CLOSE)); | |
1787 | #endif | |
1788 | ||
5260325f | 1789 | packet_close(); |
1853d1ef | 1790 | |
1791 | if (use_privsep) | |
1792 | mm_terminate(); | |
1793 | ||
5260325f | 1794 | exit(0); |
1795 | } | |
8efc0c15 | 1796 | |
4f08e98d | 1797 | /* |
1798 | * Decrypt session_key_int using our private server key and private host key | |
1799 | * (key with larger modulus first). | |
1800 | */ | |
1853d1ef | 1801 | int |
4f08e98d | 1802 | ssh1_session_key(BIGNUM *session_key_int) |
1803 | { | |
1804 | int rsafail = 0; | |
1805 | ||
3efa8ea9 | 1806 | if (BN_cmp(sensitive_data.server_key->rsa->n, |
1807 | sensitive_data.ssh1_host_key->rsa->n) > 0) { | |
4f08e98d | 1808 | /* Server key has bigger modulus. */ |
1809 | if (BN_num_bits(sensitive_data.server_key->rsa->n) < | |
3efa8ea9 | 1810 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) + |
1811 | SSH_KEY_BITS_RESERVED) { | |
1812 | fatal("do_connection: %s: " | |
1813 | "server_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1814 | get_remote_ipaddr(), |
1815 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1816 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1817 | SSH_KEY_BITS_RESERVED); | |
1818 | } | |
1819 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1820 | sensitive_data.server_key->rsa) <= 0) | |
1821 | rsafail++; | |
1822 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1823 | sensitive_data.ssh1_host_key->rsa) <= 0) | |
1824 | rsafail++; | |
1825 | } else { | |
1826 | /* Host key has bigger modulus (or they are equal). */ | |
1827 | if (BN_num_bits(sensitive_data.ssh1_host_key->rsa->n) < | |
3efa8ea9 | 1828 | BN_num_bits(sensitive_data.server_key->rsa->n) + |
1829 | SSH_KEY_BITS_RESERVED) { | |
1830 | fatal("do_connection: %s: " | |
1831 | "host_key %d < server_key %d + SSH_KEY_BITS_RESERVED %d", | |
4f08e98d | 1832 | get_remote_ipaddr(), |
1833 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n), | |
1834 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1835 | SSH_KEY_BITS_RESERVED); | |
1836 | } | |
1837 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1838 | sensitive_data.ssh1_host_key->rsa) < 0) | |
1839 | rsafail++; | |
1840 | if (rsa_private_decrypt(session_key_int, session_key_int, | |
1841 | sensitive_data.server_key->rsa) < 0) | |
1842 | rsafail++; | |
1843 | } | |
1844 | return (rsafail); | |
1845 | } | |
5260325f | 1846 | /* |
7b2ea3a1 | 1847 | * SSH1 key exchange |
5260325f | 1848 | */ |
396c147e | 1849 | static void |
1e3b8b07 | 1850 | do_ssh1_kex(void) |
8efc0c15 | 1851 | { |
5260325f | 1852 | int i, len; |
46aa2d1f | 1853 | int rsafail = 0; |
5260325f | 1854 | BIGNUM *session_key_int; |
1e3b8b07 | 1855 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
1856 | u_char cookie[8]; | |
1857 | u_int cipher_type, auth_mask, protocol_flags; | |
7fdc56c5 | 1858 | u_int32_t rnd = 0; |
5260325f | 1859 | |
aa3378df | 1860 | /* |
1861 | * Generate check bytes that the client must send back in the user | |
1862 | * packet in order for it to be accepted; this is used to defy ip | |
1863 | * spoofing attacks. Note that this only works against somebody | |
1864 | * doing IP spoofing from a remote machine; any machine on the local | |
1865 | * network can still see outgoing packets and catch the random | |
1866 | * cookie. This only affects rhosts authentication, and this is one | |
1867 | * of the reasons why it is inherently insecure. | |
1868 | */ | |
5260325f | 1869 | for (i = 0; i < 8; i++) { |
1870 | if (i % 4 == 0) | |
7fdc56c5 | 1871 | rnd = arc4random(); |
1872 | cookie[i] = rnd & 0xff; | |
1873 | rnd >>= 8; | |
5260325f | 1874 | } |
1875 | ||
aa3378df | 1876 | /* |
1877 | * Send our public key. We include in the packet 64 bits of random | |
1878 | * data that must be matched in the reply in order to prevent IP | |
1879 | * spoofing. | |
1880 | */ | |
5260325f | 1881 | packet_start(SSH_SMSG_PUBLIC_KEY); |
1882 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1883 | packet_put_char(cookie[i]); |
5260325f | 1884 | |
1885 | /* Store our public server RSA key. */ | |
fa08c86b | 1886 | packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n)); |
1887 | packet_put_bignum(sensitive_data.server_key->rsa->e); | |
1888 | packet_put_bignum(sensitive_data.server_key->rsa->n); | |
5260325f | 1889 | |
1890 | /* Store our public host RSA key. */ | |
fa08c86b | 1891 | packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); |
1892 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e); | |
1893 | packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n); | |
5260325f | 1894 | |
1895 | /* Put protocol flags. */ | |
1896 | packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1897 | ||
1898 | /* Declare which ciphers we support. */ | |
94ec8c6b | 1899 | packet_put_int(cipher_mask_ssh1(0)); |
5260325f | 1900 | |
1901 | /* Declare supported authentication types. */ | |
1902 | auth_mask = 0; | |
5260325f | 1903 | if (options.rhosts_rsa_authentication) |
1904 | auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA; | |
1905 | if (options.rsa_authentication) | |
1906 | auth_mask |= 1 << SSH_AUTH_RSA; | |
5ba55ada | 1907 | if (options.challenge_response_authentication == 1) |
5260325f | 1908 | auth_mask |= 1 << SSH_AUTH_TIS; |
5260325f | 1909 | if (options.password_authentication) |
1910 | auth_mask |= 1 << SSH_AUTH_PASSWORD; | |
1911 | packet_put_int(auth_mask); | |
1912 | ||
1913 | /* Send the packet and wait for it to be sent. */ | |
1914 | packet_send(); | |
1915 | packet_write_wait(); | |
1916 | ||
fa08c86b | 1917 | debug("Sent %d bit server key and %d bit host key.", |
1918 | BN_num_bits(sensitive_data.server_key->rsa->n), | |
1919 | BN_num_bits(sensitive_data.ssh1_host_key->rsa->n)); | |
5260325f | 1920 | |
1921 | /* Read clients reply (cipher type and session key). */ | |
54a5250f | 1922 | packet_read_expect(SSH_CMSG_SESSION_KEY); |
5260325f | 1923 | |
2d86a6cc | 1924 | /* Get cipher type and check whether we accept this. */ |
5260325f | 1925 | cipher_type = packet_get_char(); |
1926 | ||
94ec8c6b | 1927 | if (!(cipher_mask_ssh1(0) & (1 << cipher_type))) |
2d86a6cc | 1928 | packet_disconnect("Warning: client selects unsupported cipher."); |
1929 | ||
5260325f | 1930 | /* Get check bytes from the packet. These must match those we |
1931 | sent earlier with the public key packet. */ | |
1932 | for (i = 0; i < 8; i++) | |
7b2ea3a1 | 1933 | if (cookie[i] != packet_get_char()) |
5260325f | 1934 | packet_disconnect("IP Spoofing check bytes do not match."); |
1935 | ||
1936 | debug("Encryption type: %.200s", cipher_name(cipher_type)); | |
1937 | ||
1938 | /* Get the encrypted integer. */ | |
b775c6f2 | 1939 | if ((session_key_int = BN_new()) == NULL) |
1940 | fatal("do_ssh1_kex: BN_new failed"); | |
20b279e6 | 1941 | packet_get_bignum(session_key_int); |
5260325f | 1942 | |
5260325f | 1943 | protocol_flags = packet_get_int(); |
1944 | packet_set_protocol_flags(protocol_flags); | |
95500969 | 1945 | packet_check_eom(); |
5260325f | 1946 | |
4f08e98d | 1947 | /* Decrypt session_key_int using host/server keys */ |
1853d1ef | 1948 | rsafail = PRIVSEP(ssh1_session_key(session_key_int)); |
1949 | ||
aa3378df | 1950 | /* |
1951 | * Extract session key from the decrypted integer. The key is in the | |
1952 | * least significant 256 bits of the integer; the first byte of the | |
1953 | * key is in the highest bits. | |
1954 | */ | |
46aa2d1f | 1955 | if (!rsafail) { |
1956 | BN_mask_bits(session_key_int, sizeof(session_key) * 8); | |
1957 | len = BN_num_bytes(session_key_int); | |
2ceb8101 | 1958 | if (len < 0 || (u_int)len > sizeof(session_key)) { |
46aa2d1f | 1959 | error("do_connection: bad session key len from %s: " |
5ca51e19 | 1960 | "session_key_int %d > sizeof(session_key) %lu", |
1961 | get_remote_ipaddr(), len, (u_long)sizeof(session_key)); | |
46aa2d1f | 1962 | rsafail++; |
1963 | } else { | |
1964 | memset(session_key, 0, sizeof(session_key)); | |
1965 | BN_bn2bin(session_key_int, | |
1966 | session_key + sizeof(session_key) - len); | |
00be5382 | 1967 | |
8bbf1fa6 | 1968 | derive_ssh1_session_id( |
f2107e97 | 1969 | sensitive_data.ssh1_host_key->rsa->n, |
8bbf1fa6 | 1970 | sensitive_data.server_key->rsa->n, |
1971 | cookie, session_id); | |
00be5382 | 1972 | /* |
1973 | * Xor the first 16 bytes of the session key with the | |
1974 | * session id. | |
1975 | */ | |
1976 | for (i = 0; i < 16; i++) | |
1977 | session_key[i] ^= session_id[i]; | |
46aa2d1f | 1978 | } |
1979 | } | |
1980 | if (rsafail) { | |
00be5382 | 1981 | int bytes = BN_num_bytes(session_key_int); |
f6b1ba8f | 1982 | u_char *buf = xmalloc(bytes); |
00be5382 | 1983 | MD5_CTX md; |
1984 | ||
bbe88b6d | 1985 | logit("do_connection: generating a fake encryption key"); |
00be5382 | 1986 | BN_bn2bin(session_key_int, buf); |
1987 | MD5_Init(&md); | |
1988 | MD5_Update(&md, buf, bytes); | |
1989 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
1990 | MD5_Final(session_key, &md); | |
1991 | MD5_Init(&md); | |
1992 | MD5_Update(&md, session_key, 16); | |
1993 | MD5_Update(&md, buf, bytes); | |
1994 | MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH); | |
1995 | MD5_Final(session_key + 16, &md); | |
1996 | memset(buf, 0, bytes); | |
1997 | xfree(buf); | |
0572fe75 | 1998 | for (i = 0; i < 16; i++) |
1999 | session_id[i] = session_key[i] ^ session_key[i + 16]; | |
46aa2d1f | 2000 | } |
1853d1ef | 2001 | /* Destroy the private and public keys. No longer. */ |
63284fbb | 2002 | destroy_sensitive_data(); |
00be5382 | 2003 | |
1853d1ef | 2004 | if (use_privsep) |
2005 | mm_ssh1_session_id(session_id); | |
2006 | ||
7b2ea3a1 | 2007 | /* Destroy the decrypted integer. It is no longer needed. */ |
2008 | BN_clear_free(session_key_int); | |
2009 | ||
5260325f | 2010 | /* Set the session key. From this on all communications will be encrypted. */ |
2011 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type); | |
2012 | ||
2013 | /* Destroy our copy of the session key. It is no longer needed. */ | |
2014 | memset(session_key, 0, sizeof(session_key)); | |
2015 | ||
2016 | debug("Received session key; encryption turned on."); | |
2017 | ||
c242fc96 | 2018 | /* Send an acknowledgment packet. Note that this packet is sent encrypted. */ |
5260325f | 2019 | packet_start(SSH_SMSG_SUCCESS); |
2020 | packet_send(); | |
2021 | packet_write_wait(); | |
5260325f | 2022 | } |
e78a59f5 | 2023 | |
2024 | /* | |
2025 | * SSH2 key exchange: diffie-hellman-group1-sha1 | |
2026 | */ | |
396c147e | 2027 | static void |
1e3b8b07 | 2028 | do_ssh2_kex(void) |
e78a59f5 | 2029 | { |
e78a59f5 | 2030 | Kex *kex; |
e78a59f5 | 2031 | |
a8be9f80 | 2032 | if (options.ciphers != NULL) { |
6ae2364d | 2033 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
a8be9f80 | 2034 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; |
2035 | } | |
1ad64a93 | 2036 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = |
2037 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
2038 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
2039 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
2040 | ||
b2552997 | 2041 | if (options.macs != NULL) { |
2042 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
2043 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
2044 | } | |
07200973 | 2045 | if (options.compression == COMP_NONE) { |
636f76ca | 2046 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = |
2047 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none"; | |
07200973 | 2048 | } else if (options.compression == COMP_DELAYED) { |
2049 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
2050 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com"; | |
636f76ca | 2051 | } |
3efa8ea9 | 2052 | |
fa08c86b | 2053 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = list_hostkey_types(); |
2054 | ||
7a37c112 | 2055 | /* start key exchange */ |
d8ee838b | 2056 | kex = kex_setup(myproposal); |
98a58eda | 2057 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_server; |
41e5bd9a | 2058 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_server; |
98a58eda | 2059 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_server; |
2ff8003a | 2060 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_server; |
a5c9ffdb | 2061 | kex->server = 1; |
2062 | kex->client_version_string=client_version_string; | |
2063 | kex->server_version_string=server_version_string; | |
2064 | kex->load_host_key=&get_hostkey_by_type; | |
1853d1ef | 2065 | kex->host_key_index=&get_hostkey_index; |
94ec8c6b | 2066 | |
7a37c112 | 2067 | xxx_kex = kex; |
2068 | ||
c422989b | 2069 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); |
94ec8c6b | 2070 | |
d1ac6175 | 2071 | session_id2 = kex->session_id; |
2072 | session_id2_len = kex->session_id_len; | |
2073 | ||
94ec8c6b | 2074 | #ifdef DEBUG_KEXDH |
2075 | /* send 1st encrypted/maced/compressed message */ | |
2076 | packet_start(SSH2_MSG_IGNORE); | |
2077 | packet_put_cstring("markus"); | |
2078 | packet_send(); | |
2079 | packet_write_wait(); | |
2080 | #endif | |
a5c9ffdb | 2081 | debug("KEX done"); |
e78a59f5 | 2082 | } |
2362db19 | 2083 | |
2084 | /* server specific fatal cleanup */ | |
2085 | void | |
2086 | cleanup_exit(int i) | |
2087 | { | |
2088 | if (the_authctxt) | |
2089 | do_cleanup(the_authctxt); | |
6039eeef | 2090 | #ifdef SSH_AUDIT_EVENTS |
c00e4d75 | 2091 | /* done after do_cleanup so it can cancel the PAM auth 'thread' */ |
2092 | if (!use_privsep || mm_is_monitor()) | |
6039eeef | 2093 | audit_event(SSH_CONNECTION_ABANDON); |
c00e4d75 | 2094 | #endif |
2362db19 | 2095 | _exit(i); |
2096 | } |